The state of the art for actuators comprising an array of micro actuators is believed to be represented by the following, all of which are US patent documents unless otherwise indicated:                2002/0106093: The Abstract, FIGS. 1-42 and paragraphs 0009, 0023, and 0028 show electromagnetic radiation, actuators and transducers and electrostatic devices.        U.S. Pat. No. 6,373,955: The Abstract and column 4, line 34-column 5, line 55 show an array of transducers.        JP 2001016675: The Abstract shows an array of acoustic output transducers.        U.S. Pat. No. 6,963,654: The Abstract, FIGS. 1-3, 7-9 and column 7, line 41-column 8, line 54 show the transducer operation based on an electromagnetic force.        U.S. Pat. No. 6,125,189: The Abstract; FIGS. 1-4 and column 4, line 1-column 5, line 46, show an electro-acoustic transducing unit including electrostatic driving.        WO 8400460: The Abstract shows an electromagnetic-acoustic transducer having an array of magnets.        U.S. Pat. No. 4,337,379: The Abstract; column 3, lines 28-40, and FIGS. 4, 9 show electromagnetic forces.        U.S. Pat. No. 4,515,997: The Abstract and column 4, lines 16-20, show volume level.        U.S. Pat. No. 6,795,561: Column 7, lines 18-20, shows an array of micro actuators.        U.S. Pat. No. 5,517,570: The Abstract shows mapping aural phenomena to discrete, addressable sound pixels.        JP 57185790: The Abstract shows eliminating the need for a D/A converter.        JP 51120710: The Abstract shows a digital speaker system which does not require any D-A converter.        JP 09266599: The Abstract shows directly applying the digital signal to a speaker.        U.S. Pat. No. 6,959,096: The Abstract and column 4, lines 50-63 show a plurality of transducers arranged within an array.        
Methods for manufacturing polymer magnets are described in the following publications:    Lagorce, L. K. and M. G. Allen, “Magnetic and Mechanical Properties of Micro-machined Strontium Ferrite/Polyimide Composites”, IEEE Journal of Micro-electromechanical Systems, 6(4), December 1997; and    Lagorce, L. K., Brand, O. and M. G. Allen, “Magnetic micro actuators based on polymer magnets”, IEEE Journal of Micro-electromechanical Systems, 8(1), March 1999.    U.S. Pat. No. 4,337,379 to Nakaya describes a planar electrodynamics electro-acoustic transducer including, in FIG. 4A, a coil-like structure.    U.S. Pat. No. 6,963,654 to Sotme et al describes a diaphragm, flat-type acoustic transducer and flat-type diaphragm. The Sotme system includes, in FIG. 7, a coil-like structure.
Semiconductor digital loudspeaker arrays are known, such as those described in United States Patent document 20010048123, U.S. Pat. No. 6,403,995 to David Thomas, assigned to Texas Instruments and issued 11 Jun. 2002, U.S. Pat. No. 4,194,095 to Sony, U.S. Pat. No. 4,515,997 to Walter Stinger, and Diamond Brett M., et al, “Digital sound reconstruction using array of CMOS-MEMS micro-speakers”, Transducers '03, The 12th International Conference on Solid State Sensors, Actuators and Microsystems, Boston, Jun. 8-12, 2003; and such as BBE's DS48 Digital Loudspeaker Management System.
YSP 1000 is an example of a phased array speaker manufactured by Yamaha. Acoustical waveguides are known and may be designed using the principles described in conventional texts on acoustics such as, for example, Encyclopedia of Acoustics by Malcolm J. Crocker, Wiley-Inter-science; Apr. 22, 1997; Fundamentals of Acoustics by Lawrence E. Kinsler; The Science and Applications of Acoustics by Daniel R. Raichel; Principles of Vibration and Sound by Thomas D. Rossing; and Foundations of Engineering Acoustics by Frank J. Fahy.
The disclosures of all publications and patent documents mentioned in the specification, and of the publications and patent documents cited therein directly or indirectly, are hereby incorporated by reference.